Laeocathaica nordsiecki Wu, 2023

Wu, Min, Shen, Wang & Chen, Zhong-Guang, 2023, Land snail diversity in central China: revision of Laeocathaica Moellendorff, 1899 (Gastropoda, Camaenidae), with descriptions of seven new species, ZooKeys 1154, pp. 49-147 : 49

Laeocathaica nordsiecki Wu sp. nov.

Figs 2A, B , 37D , 47E, F , 49C

Type material.

Holotype HBUMM08446-spec.1, fully mature shell with immature genital system, Guoyuanxiang [郭元乡], Jiuzhaigouxian, Sichuan Province; near point (33.125506°N, 104.329876°E); 2021-IX-24, coll. Chen, Z.-G. Paratypes HBUMM08446-spec.2-3, 2 fms; HBUMM08446-spec.4-5, 2 subadults; same data of holotype. HBUMM08447-spec.1-2, 2 fms and 3 living juvs (in rearing), Qinglongcun [青龙村], Guoyuanxiang, Jiuzhaigouxian, Sichuan Province; (33.085615°N, 104.348250°E); 2020-VII, coll. Chen, Z.-G.

Measurement of holotype.

Shell height 3.7 mm, maximum diameter 10.8 mm, aperture height 3.0 mm, aperture breadth 3.3 mm, umbilicus diameter 5.0 mm, protoconch whorls 11/2, whorls 51/8.

Diagnosis.

Protoconch with dense fine granules. Umbilicus very broad, ~ 1/2 of maximum diameter. Body whorl shouldered above periphery. On shoulder with a white band. Peristome continuous. Shell strongly glossy as in Stilpnodiscus , almost transparent.

Description of shell.

Sinistral, depressed, thin but somewhat solid. Shell with 5-51/8 convex whorls. Suture impressed. Protoconch 11/2-15/8 whorls, densely with tiny granules (each ~ 10 µm long) which are obscured by erosion or weathering. Growth lines indistinct. Shell in pale brown, strongly glossy, almost transparent. Body whorl shouldered above periphery, with a white band on shoulder. Aperture oblique, round, abruptly descending in front. A white thickening within aperture and thickened callus forming a continuous peristome. Peristome expanded and slightly reflexed at lower part. Columella oblique. Umbilicus very broad, ~ 1/2 of maximum diameter. Protoconch visible through umbilicus.

Etymology.

This cute new species is named in memory of Hartmut Nordsieck, a German malacologist who showed strong interest in the snails of the South Gansu Plateau and was a good friend of the first author.

Ecology.

This species was found on bare earth with a few broken rocks.

Distribution.

Only known from two localities where the types were found.

Remarks.

The new species is the smallest species in Laeocathaica , where it is provisionally placed due to its chirality, granules on the protoconch and the similarity of the shell to that of Laeocathaica dityla . The very glossy shell also makes this species distinctive, reminiscent of the genus Stilpnodiscus Möllendorff, 1899, which appears in the phylogram (Fig. 51 ) as the sister group of all the Laeocathaica species. Undoubtedly, final generic assignment of this species will depend on further anatomical information and molecular studies.

Figures

Figure 2. A distribution map of all known species of Laeocathaica Moellendorff, 1899 except L. anceyi (Moellendorff in Ancey, 1889), L. hisanoi Pall-Gergely, 2022, and L. leucorhaphe Moellendorff, 1899 whose precise localities are not known; white dots: the localities where no Laeocathaica species was ever found B distribution of the new species described in this paper, yellow dots: L. qingchuanensis Wu, sp. nov., green dot: L. zhengpingliui Wu, sp. nov., brown dots: L. parapolytyla Wu, sp. nov., white dot: L. qiminglii Wu, sp. nov., pink dot: L. cheni Wu, sp. nov., blue dots: L. qishilii Wu, sp. nov., orange dots: L. nordsiecki Wu, sp. nov. C distribution of L. carinifera (H. Adams, 1870) (green dots), L. qingchuanensis Wu, sp. nov. (yellow dots), and L. stenochone Moellendorff, 1899 (blue dots) D distribution of L. amdoana Moellendorff, 1899 (green dots), L. distinguenda Moellendorff, 1899 (pink dots), and L. tropidorhaphe Moellendorff, 1899 (blue dots) C equivalent to the larger box in (A), B, D equivalent to the smaller box in (A).

Figure 37. A Laeocathaica zhengpingliui Wu, sp. nov., HBUMM 05553 - spec. 1, holotype B L. cheni Wu, sp. nov., HBUMM 05553 b-spec. 1, holotype C L. qingchuanensis Wu, sp. nov., HBUMM 01179 a-spec. 1, holotype D L. nordsiecki Wu, sp. nov., HBUMM 08446 - spec. 1, holotype.

Figure 47. SEM micrographs A, B Laeocathaica odophora Moellendorff, 1899, HBUMM 08430 A protoconch B teleoconch C, D L. dolani (Pilsbry, 1934), HBUMM 08439 C protoconch D teleoconch E, F L. nordsiecki Wu, sp. nov., HBUMM 08446, paratype, subadult E protoconch F teleoconch G, H L. pewzowi Moellendorff, 1899, HBUMM 08452 G protoconch H teleoconch I, J L. carinalis Chen & Zhang, 2004, HBUMM 08453 I protoconch J teleoconch K, L L. zhengpingliui Wu, sp. nov., HBUMM 05553 - spec. 2, paratype, juvenile K protoconch L teleoconch.

Figure 49. Habitats (excluding D) A, B Laeocathaica qishilii Wu, sp. nov., border of Jiuzhaigou County and Wen County C L. nordsiecki Wu, sp. nov., Guoyuanxiang, Jiuzhaigou D L. qiminglii Wu, sp. nov., an indoor photograph E L. qingchuanensis Wu, sp. nov., Dagou Nature Reserve, Qingchuan County F L. cheni Wu, sp. nov., Hengdan, Wenxian.

Figure 51. Bayesian phylogram of camaenid species (for detail see in Table 1) based on the concatenated partial mitochondrial 16 S and partial ITS 2 sequences. The tree is rooted with Helix pomatia. Numbers near nodes indicating Bayesian posterior probabilities and Maximum-likelihood bootstrap values are given as BPP ⁄ BP. Black or orange part shows the topology where the result yielded by using Bayesian-Inference method agrees with that by using Maximum-likelihood method or not, respectively. An asterisk indicates the branch is exactly one third shortened in length. Scale bar is for substitutions per site.